I’m going to use the following function,It is found that one of the parameters is not got.It is IIPoint3 using C#.
gw.HTransPoint(inp, outp);
Creating a IPoint is easy,
IPoint3 inp = g.Point3.Create(0.0f, 0.0f, 0.0f);
but I can not find a way to create a IIPoint3. Convert IIPoint3 to IPoint3 by force,failed! Anyone can help me.